PERFORCE change 37476 for review

[Sam Leffler]

http://perforce.freebsd.org/chv.cgi?CH=37476

Change 37476 by sam at sam_ebb on 2003/09/03 21:27:48

	rtrequest(RTM_DELETE, ...) locks the rtentry found by looking up
	the destination address that's specified.  This means the caller
	cannot be holding a locked reference when doing this operation so
	(for now) drop the lock and reaquire it after the delete.  Various
	alternatives were considered, including adding a delete interface
	that takes a locked rtentry, but none are as clean as this.  It
	appears that dropping+reacquiring the lock is safe in all these cases.
	
	This problem appeared when ejecting a cardbus network card configured
	with IPv6.

Affected files ...

.. //depot/projects/netperf/sys/netinet/in_rmx.c#4 edit
.. //depot/projects/netperf/sys/netinet6/in6_ifattach.c#3 edit
.. //depot/projects/netperf/sys/netinet6/in6_rmx.c#4 edit

Differences ...

==== //depot/projects/netperf/sys/netinet/in_rmx.c#4 (text+ko) ====

@@ -72,7 +72,6 @@
 	struct sockaddr_in *sin = (struct sockaddr_in *)rt_key(rt);
 	struct radix_node *ret;
 
-	/*XXX locking? */
 	/*
 	 * For IP, all unicast non-host routes are automatically cloning.
 	 */
@@ -126,12 +125,15 @@
 			    rt2->rt_flags & RTF_HOST &&
 			    rt2->rt_gateway &&
 			    rt2->rt_gateway->sa_family == AF_LINK) {
+				/* NB: must unlock to avoid recursion */
+				RT_UNLOCK(rt2);
 				rtrequest(RTM_DELETE,
 					  (struct sockaddr *)rt_key(rt2),
 					  rt2->rt_gateway, rt_mask(rt2),
 					  rt2->rt_flags, 0);
 				ret = rn_addroute(v_arg, n_arg, head,
 						  treenodes);
+				RT_LOCK(rt2);
 			}
 			RTFREE_LOCKED(rt2);
 		}
@@ -212,10 +214,13 @@
 		rt->rt_flags |= RTPRF_OURS;
 		rt->rt_rmx.rmx_expire = time_second + rtq_reallyold;
 	} else {
+		/* NB: must unlock to avoid recursion */
+		RT_UNLOCK(rt);
 		rtrequest(RTM_DELETE,
 			  (struct sockaddr *)rt_key(rt),
 			  rt->rt_gateway, rt_mask(rt),
 			  rt->rt_flags, 0);
+		RT_LOCK(rt);
 	}
 }
 

==== //depot/projects/netperf/sys/netinet6/in6_ifattach.c#3 (text+ko) ====

@@ -986,10 +986,13 @@
 	sin6.sin6_addr.s6_addr16[1] = htons(ifp->if_index);
 	rt = rtalloc1((struct sockaddr *)&sin6, 0, 0UL);
 	if (rt) {
-		if (rt->rt_ifp == ifp)
+		if (rt->rt_ifp == ifp) {
+			RT_UNLOCK(rt);
 			rtrequest(RTM_DELETE, (struct sockaddr *)rt_key(rt),
 				rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0);
-		rtfree(rt);
+			RTFREE(rt);
+		} else
+			rtfree(rt);
 	}
 }
 

==== //depot/projects/netperf/sys/netinet6/in6_rmx.c#4 (text+ko) ====

@@ -166,12 +166,15 @@
 				rt2->rt_flags & RTF_HOST &&
 				rt2->rt_gateway &&
 				rt2->rt_gateway->sa_family == AF_LINK) {
+				/* NB: must unlock to avoid recursion */
+				RT_UNLOCK(rt2);
 				rtrequest(RTM_DELETE,
 					  (struct sockaddr *)rt_key(rt2),
 					  rt2->rt_gateway,
 					  rt_mask(rt2), rt2->rt_flags, 0);
 				ret = rn_addroute(v_arg, n_arg, head,
 					treenodes);
+				RT_LOCK(rt2);
 			}
 			RTFREE_LOCKED(rt2);
 		}
@@ -272,10 +275,13 @@
 		rt->rt_flags |= RTPRF_OURS;
 		rt->rt_rmx.rmx_expire = time_second + rtq_reallyold;
 	} else {
+		/* NB: must unlock to avoid recursion */
+		RT_UNLOCK(rt);
 		rtrequest(RTM_DELETE,
 			  (struct sockaddr *)rt_key(rt),
 			  rt->rt_gateway, rt_mask(rt),
 			  rt->rt_flags, 0);
+		RT_LOCK(rt);
 	}
 }